2010-05-12

An "energy bubble" theory for the formation of ball lightning

And now for something completely different: I just read that some scientists believe ball lightning is a phenomenon caused by transcranial magnetic stimulation (TMS). This doesn't seem consistent with the huge amount of observational evidence that ball lightning is a real physical phenomenon. I want to offer a different hypothesis.

Wikipedia cites a review from 1972 that established the following commonly-claimed properties of ball lightning:

They frequently appear almost simultaneously with cloud-to-ground lightning discharge

They are generally spherical or pear-shaped with fuzzy edges

Their diameters range from 1-100 cm, most commonly 10-20 cm

Their brightness corresponds to roughly that of a domestic lamp, so they can be seen clearly in daylight

A wide range of colors have been observed, red, orange and yellow being the commonest

The lifetime of each event is from 1 second to over a minute with the brightness remaining fairly constant during that time

They tend to move, most often in a horizontal direction at a few metres per second, but may also move vertically, remain stationary or wander erratically.

Many are described as having rotational motion

It is rare that observers report the sensation of heat, although in some cases the disappearance of the ball is accompanied by the liberation of heat

Some display an affinity for metal objects and may move along conductors such as wires or metal fences

Some appear within buildings passing through closed doors and windows

Some have appeared within metal aircraft and have entered and left without causing damage

The disappearance of a ball is generally rapid and may be either silent or explosive

This all seems consistent not with an energy ball but rather with an energy bubble: a highly-charged outer surface layer of ionized particles and a highly oppositely-charged inner layer of ionized particles separated by a highly non-conductive layer -- like a bubble-shaped or topologically-closed capacitor. The attractive forces of the outer layer towards the inner layer act as a "surface tension" that gives the bubble its spherical shape but also highly compresses the central air cavity of the bubble, until the electrostatic attractive force pulling the membrane complex inward is equal to the reactive force of the air pressure inside the bubble pushing outward.

This model explains the following:

The spherical shape of the lightning ball. (In the case of pear-shaped ball lightning, as shown in the "UFO or something?" video below, it is simply two bubbles stuck to each other with a central dividing surface, as frequently observed when blowing soap bubbles.) A surface tension gradient is required to induce the Maraghoni effect for bubble formation, which would be present for an electric field surrounding a plasma. This gradient would also explain the fuzzy appearance of lightning balls.

The tendency of the bubble to be attracted to some objects and surfaces and approach or glide along other surfaces. This can be explained by the difference in electric field potential of the two bubble surfaces relative to the charge of the object or surface in question.

The reports of popping or even explosion when the lightning ball destabilizes. This is the bubble popping, releasing the potentially huge interior air pressure, and causing a powerful arc due to electrical breakdown between the two bubble surfaces

The reports of sulfurous smell after the ball pops. This is the production of ozone from the electrical discharge between the surfaces.

Two questions remain: how would such a bubble form, and what could form the insulating layer?

It turns out that induced current in a fully ionized gas becomes unstable or breaks down in a DC electric field of sufficient strength, i.e. above a critical threshold [Nonlinear Electrical Conductivity of a Fully Ionized Gas, Kun-Mu Chen, 1962]. Thus it is conceivably possible to wedge a layer of fully ionized gas (plasma, with net charge close to zero) between a layer of positive ions and a layer of negative ions, if done with sufficient speed and with sufficient induced field strength that current flow through the insulating layer is eliminated before the charges have a chance to equalize.

As far as bubble formation, a lightning bolt would need to topologically enclose a pocket of air to trigger the phenomenon, though I don't know if it would also require a particular mixture of gasses, air moisture content or other conditions to start with. I hypothesize you might be able to create ball lightning by blowing bubbles in front of a powerful enough van de Graff generator. Can anybody test this?

NOTE: People have created plasmoids in a microwave by using smoke clouds emanating from a just-extinguished match. These are balls of ionized gas, and are not the same as the energy bubbles as I am describing here, but they also differ in properties from ball lightning, such as the fact that they disappear within 30ms of the microwave source being switched off.

UPDATE: I emailed Antonio Pavão (see the video below) to ask him his opinion of this theory, and he said: Thank you for sending your BL energy bubble model for my appreciation. It is an interesting model, but I would suggest a quantitite treatment in order to prove the existence of the "highly-charged outer surface layer of ionized particles and a highly oppositely-charged inner layer of ionized particles separated by a highly non-conductive layer". Recently V. Bichkov has proposed a “quasi-solid-vitrified” cover layer around the BL, but I´m still not sure about his results. The existence of this layer is also claimed in the paper “On phenomenon of light radiation from miniature balls immersed in water” from Torchigin V. P., Torchigin A. V., Institute of Informatics Problems, Russian Academy of Sciences, Nakhimovsky prospect 36/1, 119278, Moscow, Russia. Our model considers a metal core surrounded by an atmosphere of silicon oxides.